I recently have a mechanic replaced my 2001 Volvo S40 catalytic converter (with an aftermarket parts, not original). When I got the car back, oil leak is evident wherever I parked, whenever I take it for a drive. There's also burning oil smell that goes inside the car. My mechanic said that the oil leak was there even before the catalytic converter was replaced. The smell got stronger because now the catalytic converter is working okay, according to him. He said the oil leak reaches the catalytic converter.
While it was at the shop, I was told that they had to remove the turbo before everything can be installed back.
Is it possible that the engine oil leak is related to the work done with the catalytic converter replacement?